OverlayFS support for fstab
Add overlayfs (lowerdir) mount entry support to fstab.
overlay <final dir> overlay lowerdir=/1:/2
E.g.
overlay /vendor overlay lowerdir=/odm/vnd_ovl1/1:/odm/vnd_ovl2
Test: Ensure mounting with fstab overlayfs entry
Change-Id: Ib025e203f8ac1836ab62dfa96fb14e8e108f82fb
diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index 42bf356..853b24d 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -298,6 +298,8 @@
if (!ParseByteCount(arg, &entry->zram_backingdev_size)) {
LWARNING << "Warning: zram_backingdev_size= flag malformed: " << arg;
}
+ } else if (StartsWith(flag, "lowerdir=")) {
+ entry->lowerdir = arg;
} else {
LWARNING << "Warning: unknown flag: " << flag;
}
diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index cb09383..9a94d79 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -92,6 +92,10 @@
return false;
}
+bool fs_mgr_overlayfs_mount_fstab_entry(const std::string&, const std::string&) {
+ return false;
+}
+
std::vector<std::string> fs_mgr_overlayfs_required_devices(Fstab*) {
return {};
}
@@ -1295,6 +1299,18 @@
}
}
+bool fs_mgr_overlayfs_mount_fstab_entry(const std::string& lowers,
+ const std::string& mount_point) {
+ if (fs_mgr_overlayfs_invalid()) return false;
+
+ std::string aux = "lowerdir=" + lowers + ",override_creds=off";
+ auto rc = mount("overlay", mount_point.c_str(), "overlay", MS_RDONLY | MS_NOATIME, aux.c_str());
+
+ if (rc == 0) return true;
+
+ return false;
+}
+
bool fs_mgr_overlayfs_mount_all(Fstab* fstab) {
auto ret = false;
if (fs_mgr_overlayfs_invalid()) return ret;
diff --git a/fs_mgr/include/fs_mgr_overlayfs.h b/fs_mgr/include/fs_mgr_overlayfs.h
index d45e2de..ac95ef5 100644
--- a/fs_mgr/include/fs_mgr_overlayfs.h
+++ b/fs_mgr/include/fs_mgr_overlayfs.h
@@ -27,6 +27,7 @@
android::fs_mgr::Fstab fs_mgr_overlayfs_candidate_list(const android::fs_mgr::Fstab& fstab);
bool fs_mgr_overlayfs_mount_all(android::fs_mgr::Fstab* fstab);
+bool fs_mgr_overlayfs_mount_fstab_entry (const std::string& lowers, const std::string& mount_point);
std::vector<std::string> fs_mgr_overlayfs_required_devices(android::fs_mgr::Fstab* fstab);
bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,
bool* change = nullptr, bool force = true);
diff --git a/fs_mgr/include_fstab/fstab/fstab.h b/fs_mgr/include_fstab/fstab/fstab.h
index 2704e47..f33768b 100644
--- a/fs_mgr/include_fstab/fstab/fstab.h
+++ b/fs_mgr/include_fstab/fstab/fstab.h
@@ -55,6 +55,7 @@
std::string vbmeta_partition;
uint64_t zram_backingdev_size = 0;
std::string avb_keys;
+ std::string lowerdir;
struct FsMgrFlags {
bool wait : 1;
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index 3faf430..a733839 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -331,6 +331,12 @@
if (devices.empty()) {
return true;
}
+ // excluding overlays
+ for (auto iter = devices.begin(); iter != devices.end(); ) {
+ if (*iter=="overlay") iter = devices.erase(iter);
+ else iter++;
+ }
+
return block_dev_init_.InitDevices(std::move(devices));
}
@@ -542,6 +548,11 @@
continue;
}
+ if (current->fs_type == "overlay") {
+ ++current;
+ continue;
+ }
+
// Skip raw partition entries such as boot, dtbo, etc.
// Having emmc fstab entries allows us to probe current->vbmeta_partition
// in InitDevices() when they are AVB chained partitions.
@@ -591,6 +602,13 @@
};
MapScratchPartitionIfNeeded(&fstab_, init_devices);
+ for (auto current = fstab_.begin(); current != fstab_.end(); ) {
+ if (current->fs_type == "overlay") {
+ fs_mgr_overlayfs_mount_fstab_entry(current->lowerdir, current->mount_point);
+ }
+ ++current;
+ }
+
fs_mgr_overlayfs_mount_all(&fstab_);
return true;